Spark ignition for otto engines



Dec. 10, 1968 F. HANKE 3,415,235

SPARK IGNITION FOR OTTO ENGINES Filed May 31, 1966 alawi United States Patent Office Patented Dec. 10, 1968 3,415,235 SPARK IGNITION FOR OTTO ENGINES Friedrich Hanke, Kiel, Germany, assignor to Maschinenfabrik Buckau, R. Wolf Aktiengesellschaft, Grevenbroich, Germany Filed May 31, 1966, Ser. No. 553,762 Claims priority, application Germany, May 28, 1965, M 65,388 Claims. (Cl. 123-149) ABSTRACT OF THE DISCLOSURE A transmission arrangement especially for transmitting rotation between an output shaft of an Otto engine and the' input shaft of the magneto of the spark ignition system of the engine, in which the output shaft is rotatably mounted about a fixed axis in a housing and wherein the input shaft is rotatably carried by an adaptor mounted on the housing adjustable between a plurality of different position in which the input shaft is located at different distances from the output shaft and in which the transmission arrangement includes a gear train having at least one gear which is replaceable by different gear to thereby change the ratio of the transmission when the adaptor is adjusted to change the distance between the shafts.

The present invention relates to internal combustion engines in general, and more particularly to improvements in operative connections between spark ignition systems and Otto engines. Still more particularly, the invention relates to a novel adapter which enables a spark ignition system, especially a magneto, to be utilized in Otto engines having different numbers of cylinders.

It is well known that an Otto engine requires a spark ignition system which ignites the compressed fuel-air mixture in the cylinders and that the spark ignition system which includes a magneto must be coupled with the crankshaft of the engine to drive the distributor rotor of the magneto so that the rotor can direct the electrical impulses in proper order to the cylinders. At the present time, it is considered necessary to produce a different magneto ignition system for each type of engine, i.e., an ignition system used in an Otto engine with say four cyl inders cannot be used in an engine wherein the number of engines exceeds or is less than four.

'In order to reduce the cost, manufacturers of Otto engines now resort to a novel method of assembling cylinder blocks of prefabricated units so that such units may be joined to form blocks of three, four, five or seven cylinder engines, depending on the desired power of the engine. It is therefore desirable to provide a spark ignition system which can be utilized in connection with all such types of engines, and a very important object of my invention is to provide a spark ignition system which may be installed in Otto engines having any desired number of cylinders.

Another object of the present invention is to provide a magneto ignition system which can be used in connec tion with Otto engines having different numbers of cylinders and which is constructed and assembled in such a way that its transfer from an engine with, say four cylinders into an engine with say six cylinders necessitates a minimum of work and can be completed within short periods of time.

A further object of the invention is to provide a novel adapter which may be utilized to connect a spark ignition system with Otto engines having a greater or lesser number of cylinders.

An additional object of the invention is to provide a novel gear train between the output shaft of an Otto engine and the rotary input member of a spark ignition system.

A concomitant object of the instant invention is to provide a very simple method of changing the transmission ratio between the crankshaft of an Otto engine and the distributor rotor of a magneto ignition system.

Briefly stated, one feature of my present invention resides in the provision of an Otto engine which comprises a housing (for example, a block which may be assembled of two or more units as outlined hereinbefore), a rotary output member mounted in the housing, a spark ignition system having a rotary input member which drives the distributor rotor, adapter means supporting the spark ignition system and detachably mounted on the housing for movement to a plurality of different positions in each of which the input member of the spark ignition system is located at a different distance from the output member, and transmission means including a gear train which transmits motion from the output member to the input member. At least one gear of the gear train is replaceable by one. or more different spare gears to thereby change the ratio of the transmission when the adapter means is adjusted to change the distance between the input member and the output member.

In accordance with a more specific feature of my invention, the adapter means comprises a holder which can be attached to the housing in a plurality of angular positions and the input member is eccentric with referenec to the axis about which the holder is adjustable. The exchangeable gear may be constituted by a pinion which is detachably secured to the input member, either directly or through the intermediary of a suitable flange or a like carrier.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved spark ignition system itself, however, both as to its construction and the mode of installing the same, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a fragmentary section through the housing of an Otto engine and illustrates a spark ignition system in a first position;

FIG. 2 is a view as seen from the line II--II of FIG. 1, two additional positions of the spark ignition system being indicated by phantom lines; and

FIG. 3 is a section similar to that shown in FIG. 1 and illustrates a carrier for one gear of the transmission in two different positions.

Referring to the drawings in detail, FIG. 1 shows a housing 1 which forms part of an Otto engine having a .given number of cylinders. The front wall 1a of this housing 1 is provided with a circular opening 2 which is closed by a disk-shaped holder or cover 3 forming part of an adapter and integrally or detachably connected with a supporting bracket 5 which carries a spark ignition system in the form of a magneto 4. Cover 3 and bracket 5 form bracket means supporting the magneto 4. The connecting means for detachably securing the cover 3 to the housing 1 comprises a set of screws 6 or similar fasteners which are disposed on a circle (see FIG. 2) and are equidistant from each other. The stem of each screw 6 is driven into a tapped bore provided in the front wall 1a of the housing 1 adjacent to the opening 2.

The clutch 8 of the magneto 4 drives a distributor rotor 4a and receives motion from a rotary input shaft 7 which is journalled in a bearing sleeve 3b provided in a hub 3a of the cover or holder 3. The hub 3a is eccentric with reference to the circle formed by the screws 6, i.e., with reference to the axis 3x of the cover 3.

The housing 1 defines an internal chamber 112 into which the shaft 7 extends, and this chamber 1b further accommodates a pair of coaxial spur gears 9, 10 forming part of a transmission and having different diameters. The common axis of the gears 9, 10 and output shaft 10 is parallel to the axis of the shaft 7. The gears 9, 10 are driven by the output shaft 1c.

The end portion 7a of the input shaft 7 extends beyond the hub 3a and detachably supports a hub 11 having a disk-shaped carrier or flange 11a for a spur gear 12 which meshes with the gear 10. The connecting means for detachably securing the gear 12 to the flange 11a comprises a set of screws 13.

In order to change the distance between the common axis of the gears 9, 10 and the axis of the driven input shaft 7, the operator must remove the screws 6 and change the angular position of the cover 3 with reference to the axis 3x. The operator then replaces the gear 12 with a gear of different diameter and reattaches the cover 3 to the front wall 1a but in a different angular position. For example, and as shown in FIG. 2, the input shaft 7 of the magneto 4 may be moved from a solid-line first position I to a second position II which is indicated by phantom lines. The pitch circle of the gear 12 in the position I of the input shaft 7 is shown at 12'. In the position 11, the shaft 7 must carry a different gear having a larger pitch circle 12" so that such different gear will mesh with the gear 10 whose pitch circle is indicated by the numeral 10'. Such angular adjustment will take place when the operator wishes to reduce the transmission ratio between the output shaft 10 which drives the gears 9, 10 and the input shaft 7.

If the input shaft 7 is moved to the position 111 of FIG. 2, it must be provided with a smaller gear which can mesh with the gear 10, or with a gear having a pitch circle 12'" so that such gear can mesh with the gear 9 whose pitch circle is shown at 9'.

FIG. 3 illustrates that the position of the hub 11 may be reversed so that its flange 11a will be located nearer to or further away from the cover 3. When the flange 11a is nearer to the cover, it can carry a gear having a pitch circle 12" and meshing with the gear 9. When the position of the hub 11 is reversed, the flange 11a may carry the gear 12 or a gear having a pitch circle 12 and meshing with the gear 10. It is also clear that the input shaft 7 can carry two gears each of which meshes with one of the gears 9, 10, that the chamber 1b may accommodate a single gear 9'or 10 or three or more gears.

In order to allow for very accurate selection of the angular position of the cover 3, the latter may be provided with holes or slots which receive the stems of screws 6 with at least some clearance so that the operator can change, within limits, the angular position of the cover 3 and the distance between the input shaft 7 and the common axis of gears 9, .10 before the screws 6 are drawn tight. One such slot 3c of the cover 3 is shown in FIG. 2.

It will be seen that, by the simple expedient of providing an adaptor which comprises the cover 3 with bracket and the screws 6, the magneto 4 may be placed at any desired distance from the gears that transmit to its input shaft motion from the output shaft of an Otto engine and that such changes in distance may be carried out by changing the angular position of the cover 3. While it in equally possible to change the transmission ratio between the output shaft 10 of the Otto engine and the input shaft 7 of the magneto 4 by providing the engine with one or more spare gears 9 and/or 10, the solution shown in FIGS. 1 to 3 has been found to be very satisfactory because a single set of gears suffices to allow for utilization of a single type of magneto in engines having different numbers of cylinders.

An important advantage of the hub 11 with flange 11a is that the cost involved in the production of gears 12 is reduced to a minimum. Also, the position of the hub 11 need not necessarily be reversed when the operator decides to drive the input shaft 7 from the gear 9 instead of from the gear 10, or vice versa. This will be readily understood since the gear 12 can be affixed to either side of the flange 1111.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is:

1. In a spark ignition system, stationary support means; an output shaft mounted on said support means rotatably about a fixed axis; bracket means; a magneto mounted on said bracket means and having a magneto shaft parallel to said output shaft; means for adjustably mounting said bracket means on said support means between a plurality of different positions along an arcuate path in which said magneto shaft is located at different distances from said output shaft; and transmission means including a gear train for transmitting motion from said magneto shaft to said output shaft, said gear train including at least one gear replaceably mounted on one of said shafts so as to permit its replacement by a different gear to thereby change the ratio of transmission when the bracket means is adjusted between said different positions thereof.

2. In a spark ignition system as defined in claim 1, wherein said one gear which is replaceable by a different gear is replaceably mounted on said magneto shaft for rotation therewith and said gear train including at least one additional gear mounted on said output shaft for rotation therewith.

3. In a spark ignition system as defined in claim 2, and including a second additional gear mounted on said output shaft and adapted to be brought in mesh with said one gear and said different gear.

4. In a spark ignition system as defined in claim 2, wherein all of said gears are spur gears and wherein said magneto and output shafts have parallel axes.

5. In a spark ignition system as defined in claim 4, wherein said bracket means is mounted on said support means adjustable about a predetermined axis parallel to said axes in a plurality of angularly displaced positions, and in which the axis of said magneto shaft is eccentrically arranged with respect to said predetermined axis.

6. In a spark ignition system as defined in claim 5, and including a second additional gear mounted on said output shaft and adapted to be brought in mesh with said one and said different gear.

7. In a spark ignition system as defined in claim 6, and including a hub fixed to said magneto shaft and having a carrier, and connecting means detachably securing said one gear to said carrier.

8. In a spark ignition system as defined in claim 7, wherein said carrier is in form of a flange integral with said hub and said one gear is connectable to either side of said flange.

9. In a spark ignition system as defined in claim 7, wherein said hub is separable from and is attachable to said magneto shaft in two different positions and said 5 6 carrier is nearer to one than to the other axial end of said References Cited hub, said carrier being nearer to one of said additional UNITED STATES PATENTS gears in one position of said hub and nearer to the other additional gear in the other position of said hub. 2819'622 1/1958 Haxton 74 353 10. In a spark ignition system as defined in claim 2, 5 3,229,540 1/1966 Baranowskl 74-354 wherein said stationary support means is a housing forming part of an Otto engine, said at least one additional LAURENCE GQODRIDGE Pnmary Examiner gear being mounted in said housing, and wherein said magneto forms part of a spark ignition system for said 74 353; 123 148 Otto engine. 10 

